Pressure operated switch and actuator combination



S p {1 11 E. M mLLAN 3,149,213

' PRESSURE OPERATED-SWITCH AND Ac'ruA'roR COMBINATION,

Filed Dec. 16, 1960 /NVN7'0R PoBERTEMc/IILLAN BY Mvw Arromvzvs United States Patent 3,149,213 PRESSURE OPERATED SWITCH AND ACTUATOR CQMBINATION Robert E. MacMillan, Detroit, Mich, assignor to The Delman Company, Cookeville, Tenn., a corporation of Tennessee Filed Dec. 16, 1960, Ser. No. 76,247 2 Claims. (Cl. 20083) combined with an actuator therefor which eliminates the necessity of separate mountings for the switch and actuator and of a mechanical actuating connection therebetween.

Yet another object of this invention is to provide a switch in combination with an actuator used in a vacuum system, so that the switch is operated by application of the vacuum and requires no additional elements for operation thereof in the system.

Another object of this invention is to provide an electric switch having a tubular contact secured to a vacuum actuator including a movable diaphragm, and wherein the switch includes a tapered contact coaxially movable within the tubular contact for engagement therewith as determined by movement of the diaphragm.

It is another object of this invention to provide a combined electric switch and vacuum actuator as characterized above which is simple, inexpensive and efiicient in operation.

These objects and other features and advantages of this invention will be readily apparent upon reference to the following description when taken into consideration with the accompanying drawings, wherein:

FIG. 1 is a perspective view of the combined electric switch and vacuum actuator of this invention;

FIG. 2 is a sectional view taken along the line 22 in FIG. 1, showing the actuator and switch combination in one position, with certain parts broken away for purposes of clarity; I

FIG. 3 is a sectional view similar to FIG. 2, and showing the actuator and switch combination in another position; and

FIG. 4 is an enlarged sectional view taken along the line 44 in FIG. 1.

Referring now to FIG. 1, the combined switch-actuator of this invention is indicated generally at 10, and includes a substantially cylindrical casing 11 forming part of a vacuum actuator 12 (FIG. 2), and a tubular body 13 forming part of an electric switch 14. A mounting bracket 16 integral with the casing 11 is provided for the switchactuator 10. Although many uses of this combination are envisioned, a particular one is the placement of the switchactuator in an automobile windshield clearing apparatus wherein the source of suction or subatmospheric pressure at the intake manifold of the automobile engine is applied to the vacuum actuator 12 for operating the switch 14 to in turn open and close an electric power unit circuit for the clearing apparatus.

The vacuum actuator casing or housing 11 includes a bleed plug housing 17 (FIG. 2) integral therewith and in which is formed an internally threaded opening 18 communicable by a passage 21 with the interior of a chamber 19 formed in the housing 11. A hose connection 22 is inserted through the casing 11 for communicating a source of subatmospheric pressure with the cham- 3,149,213 Patented Sept. 15, 1964 ber 19. For the purpose of permitting air under atmospheric pressure to bleed into the chamber 19 at a predetermined rate, a plurality of plugs 23 of a fibrous, porous material such as felt, are stacked over a ring 24 placed on the bottom wall of the opening 18. The felt plugs 23 provide a desired air restriction while maintaining a suificient area for dirt tolerance. A fibrous washer 26 is placed on the top of the opening 18, and a slab-sided screw 27 is then inserted in the opening so that as the head of the screw 27 clamps down on the washer 26, the flat side of the screw 27 provides an air passage 28 between the washer 26 and the plugs 23.

One end 25 of the chamber 19 is formed with a cylindrical pocket for seating a coil spring 29 therein, and the other end of the chamber 19 is enclosed by a cover 31. The cover 31 is secured to the body 13 of the switch 14 and also functions to clamp the periphery 32 of a flexible diaphragm 33 into a grooved flange 34 of the casing 11. A flat disc 36 is mounted on one side of the diaphragm 33, and a cup-shaped piston 37 is mounted on the other side thereof and against which the coil spring 29 is biased. The disc 36, piston 37 and the central portion of the diaphragm 33 are held in assembled relation by a screw 38 which is engageable with the electric switch 14. For reasons hereinafter described, the screw 38 is of a nonconductive material.

The body 13 of the electric switch 14 is also of a nonconductive material and is provided at its inner end with a flange 41 (FIG. 2) for insertion into an opening provided therefor in the cover 31. A large bore 42 in the switch body 13 at its end 43 opposite the flange 41, includes a slot 44 extended longitudinally of the bore 42 as illustrated in FIG. 2. Inwardly of the bore 42 is a much smaller and shorter bore 46 which leads to a slightly larger bore 47 ending in a circular cavity 48 at the flange end 41 of the switch body 13. v

A tubular electrical contact 49 (FIGS. 2 and 4) having a radially extending terminal 51 is forcibly fitted into the bore 42, with the terminal 51 extended through the slot 44. The contact 49 has a bore 52 (FIG. 4) formed therein which is axially aligned with the switch body bore 46, and the outer end of which is formed with a conically shaped cavity 53, as best illustrated in FIG. 2. For coaction with the stationary contact 49, there is provided a movable electrical contact 54 which includes a stem 56 coaxially inserted for reciprocal movement through the bore 52 of the contact 49, and through the bores 46 and 47 of the switch body 13.

A collar or stop member 57 (FIG. 2) is secured on the inner end of the stem 56, which, upon engagement by the spring biased screw 38 of the vacuum actuator 12, is forced into the cavity 48. A small coil spring 58 (FIG. 3) is inserted between the stop member 57 and a shoulder 60 formed at the junction of the bores 46 and 47 for normally biasing the stop member and thus the entire movable contact 54 toward the screw 38 or i to the right, as illustrated in FIG. 3. At the outer end of the stem 56 is secured an electrically conductive plug 59 having a tapered or frustro-conical shape, and which is adapted to firmly seat in a nested relation within the conical cavity 53. A terminal 61 is secured to the plug 59.

Since the bore 52 of the stationary contact 54 is larger and in axial alignment with the small bore 46 of the switch body 13, the stem 56 of the movable contact 54 is in a substantial clearance relation with the bore 52. Thus, should the stem 56 be of a conductive material, engagement with the normally hot contact 49 is eliminated. Additionally, as the stem 56 reciprocates coaxially of the contact 52, the plug 59 moves coaxially of the cavity 53.

In operation, assume that the switch-actuator is a part of a conventional automotive windshield clearing apparatus wherein an operator-controlled suction line is attached to the hose connection 22. Thus, a subatmospheric pressure can be applied to the compartment 62 (FIG. 2) on the motor or right side of the diaphragm 33. As atmospheric air is in the compartment 63 on the working or'left side of the diaphragm 33, by virtue of the various bores in the switch body 13 communicating the compartment 63 to the atmosphere, the diaphragm 33 is forced toward the right until the piston 37 contacts a casing wall 64, as shown in FIG. 3.

This movement of the diaphragm away from the stop member 57 enables the small spring 58 to force the stop member 57 toward the right and out of the cavity 48 (FIG. 3) whereby to seat the plug 59 in the cavity 53. Assuming that the stationary terminal 51 is connected \through to the vehicle battery (not shown), and that the movable terminal 61 is connected to an electrically operated power unit for the windshield clearing apparatus, it can readily be seen that this closing of the circuit energizes the power unit. 7

When the application of the subatmosphericpressure is removed, the diaphragm 33 moves to the left from the FIG. 3 position at a rate depending upon the rate of air bleed in the bleed opening 18. Upon the screw 33 engaging the stop member 57, and since the pressure of the large coil spring 29 is greater than that of the smaller coil spring 58, the stem 56 is moved to the left, as shown in FIG. 2, until the stop member 57 seats in the cavity 48. As a result, the plug 59 is moved out of the recess 53, thus disengaging the contacts 49 and 54 and opening the electric circuit to de-energize the windshield cleaning apparatus power unit. A desired time delay in the operation of the switch 14 for a certain time interval subsequent to the shutting off of the suction pressure, can be obtained by manipulating the screw 27 to adjust the compression of the bleed plugs 23.

Although a preferred embodiment of this invention has been disclosed herein, modifications can be made therein without departing from the scope of the invention as defined by the appended claims.

I claim:

1. In combination, a vacuum actuator including a 9 housing having a chamber formed therein, a diaphragm member movably mounted in said chamber, means mounted in said chamber biasing said diaphragm member toward a first position, said diaphragm member responsive to the application of a subatmospheric pressure thereagainst to overcome said bias means and move said diaphragm member into a second position, means for bleeding atmospheric air into said chamber on one side of said diaphragm member, and electric switch means including a body member having a bore formed therein secured to said housing, a tubular electric contact secured to said body member in axial alignment with said bore and having a conical cavityformed therein, a rod member extended through said bore and engageable with said diaphragm member in the first position, a frustro-conical shaped electrical contact mounted on said rod member .4 g and movable therewith coaxially of said bore and said tubular electrical contact into and out of a seated engagement within said cavity, and means biasing said contacts together, said contacts being moved into spaced relation by coaction of the diaphragm member with the rod member when said diaphragm member is moved to said first position by the diaphragm member biasing means and said contacts being moved into engagement by said contact biasing means when said diaphragm member is moved to said second position out of engagement with the rod members. 1

2. In combination, a vacuum actuator including a housing having a chamber formed therein, a diaphragm member movably mounted in said chamber, means mounted in said chamber biasing said diaphragm member toward a first position, said diaphragm member responsive to the application of a subatrnosp'neric pressure thereagainst, to overcome said bias means and to move said diaphragm member into a second position, means for bleeding atmospheric air into said chamber on a side of said diaphragm member operatively associated with said bias means, and electric switch means including a body member having a bore formed therein secured to said housing, a tubular electric contact secured to said body member in axial alignment with said hole and having a conical cavity formed therein, a rod member reciprocally mounted in said bore and extended coaxially through said tubular contact in spaced relation with the inner surface of said tubular contact, the inner end of said rod member enlarged and engageable with said diaphragm member in the first position, a cone-shaped electrical contact adapted for complementary seating engagement within said cavity secured on said rod member and movable therewith coaxially of said tubular contact, and means inserted between said body member and said enlarged inner endbiasing said contacts together, said contacts being moved into spaced relation by coaction of the diaphragm member with the rod member when said diaphragm member is moved to said first position by the diaphragm member biasing means and said contacts being moved into engagement when said diaphragm member is moved to said second position out of engagement with the rod members.

References Qited in the file of this patent UNITED STATES PATENTS 

1. IN COMBINATION, A VACUUM ACTUATOR INCLUDING A HOUSING HAVING A CHAMBER FORMED THEREIN, A DIAPHRAGM MEMBER MOVABLY MOUNTED IN SAID CHAMBER, MEANS MOUNTED IN SAID CHAMBER BIASING SAID DIAPHRAGM MEMBER TOWARD A FIRST POSITION, SAID DIAPHRAGM MEMBER RESPONSIVE TO THE APPLICATION OF A SUBATMOSPHERIC PRESSURE THEREAGAINST TO OVERCOME SAID BIAS MEANS AND MOVE SAID DIAPHRAGM MEMBER INTO A SECOND POSITION, MEANS FOR BLEEDING ATMOSPHERIC AIR INTO SAID CHAMBER ON ONE SIDE OF SAID DIAPHRAGM MEMBER, AND ELECTRIC SWITCH MEANS INCLUDING A BODY MEMBER HAVING A BORE FORMED THEREIN SECURED TO SAID HOUSING, A TUBULAR ELECTRIC CONTACT SECURED TO SAID BODY MEMBER IN AXIAL ALIGNMENT WITH SAID BORE AND HAVING A CONICAL CAVITY FORMED THEREIN, A ROD MEMBER EXTENDED THROUGH SAID BORE AND ENGAGEABLE WITH SAID DIAPHRAGM MEMBER IN THE FIRST POSITION, A FRUSTRO-CONICAL SHAPED ELECTRICAL CONTACT MOUNTED ON SAID ROD MEMBER AND MOVABLE THEREWITH COAXIALLY OF SAID BORE AND SAID TUBULAR ELECTRICAL CONTACT INTO AND OUT OF A SEATED ENGAGEMENT WITHIN SAID CAVITY, AND MEANS BIASING SAID CONTACTS TOGETHER, SAID CONTACTS BEING MOVED INTO SPACED RELATION BY COACTION OF THE DIAPHRAGM MEMBER WITH THE ROD MEMBER WHEN SAID DIAPHRAGM MEMBER IS MOVED TO SAID FIRST POSITION BY THE DIAPHRAGM MEMBER BIASING MEANS AND SAID CONTACTS BEING MOVED INTO ENGAGEMENT BY SAID CONTACT BIASING MEANS WHEN SAID DIAPHRAGM MEMBER IS MOVED TO SAID SECOND POSITION OUT OF ENGAGEMENT WITH THE ROD MEMBERS. 